1. Technical Field
This invention related to colorimetric indicators, more particularly to pH colorimetric indicators which are chemical substances that change color over a given pH range and the user application apparatus to contain same.
2. Description of Prior Art
Prior art testing systems to determine the quality of motor oil have been developed in which the pH of the oil indicates the level of contaminants which relate directly to wear issues in the engine. Modern lubricating oil has a hydrocarbon base and a variety of chemical additives to enhance the oil effectiveness and cleaning abilities. Typically, such additives impart alkalinity to the oil over time when the oil becomes contaminated with insoluble and soluble contaminants including acidic oxidation products. Examples of such prior art chemically treated test strip materials for determining the effective pH and therefore quality of the oil can be seen in U.S. Pat. Nos. 2,770,530 and 3,580,704.